1. Field of the Invention
The present invention relates to roofing and sealant compositions. More particularly, the present invention relates to roofing and sealing compositions containing coal tar pitch.
2. Description of the Prior Art
It is known to use coal tar pitch of an appropriate softening point in roofing and other sealant applications. However, the use of coal tar pitch in such applications presents several problems. For one, because of its tendency to flow or cold creep, heretofore coal-tar-pitch-based compositions have not generally been suitable for use on sloped surfaces or as a flashing material. Additionally, because of the fact that coal tar pitch contains carcinogenic materials, it is desirable to minimize heating used in sealant applications such as roofing since high temperatures can result in hazardous volatilization of such carcinogenic materials.
Because of these problems, it would be desirable to have a coal tar pitch composition that could be used in membranes requiring far less heating for application and thus less volatilization of hazardous materials. Such membranes include a reinforcement or substrate such as a polyester cloth, fiberglass cloth, mixed polyester-fiberglass cloths or the like impregnated and/or coated with the coal tar pitch composition. It is also common for the substrate to incorporate a binder that prevents the substrate from stretching in roofing applications.
Additionally, it is desirable to have a coal tar pitch composition for use in roofing and other sealant applications, e.g., roofing membranes, that could be used on sloped surfaces or in flashings and that was not subject to objectionable flow or cold creep.